No one has the answers.
It's ....ALL.... been tried before.
You would think a good start would be less crowding of our planet, yet at the time of Christ we had about 300 million people on the entire planet.
Even then we were collectively a conquering species that killed the most benevolent entity that ever was known to grace our savage planet.
The only thing left to try would be total universal-ism.
No individuality,1 benevolent deity, universal law, classless society, identical living arrangements for a population of no more than 1/2 billion, Every citizen dedicated to a lifetime appointed craft/Guild/Apprenticeship to benefit the greater good of the community.....
All this on a small apportioned part of the Earth with nothing for resources but recycled waste discarded by thoughtless prior generations of plague animals.
The only governance is strict obeyance enforced by immutable laws up to and including the death penalty.
That, as bleak as it sounds, is most probably the only way forward for the most worthy among'st us.
{really..what i've just described was Adam's generation through the Seth lineage...they just had to come down from that mountain and see what Cain had to offer....}{A flute and a lute, a snoot full of 'toot'}
But really now...individuality is so much more fun....along with all the trash it produces.
I only included the 1 benevolent entity because i think there may be something to 'Jungian' archetypes and all....i think we actually require a deity{among'st other fantasy's} to stay sane.